/*-------------------------------------------------------------------------
 *
 * int8.c
 *      Internal 64-bit integer operations
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * This source code file contains modifications made by THL A29 Limited ("Tencent Modifications").
 * All Tencent Modifications are Copyright (C) 2023 THL A29 Limited.
 * 
 * IDENTIFICATION
 *      src/backend/utils/adt/int8.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>
#include <limits.h>
#include <math.h>

#include "funcapi.h"
#include "libpq/pqformat.h"
#include "utils/int8.h"
#include "utils/builtins.h"


#define MAXINT8LEN        25

#define SAMESIGN(a,b)    (((a) < 0) == ((b) < 0))

typedef struct
{
    int64        current;
    int64        finish;
    int64        step;
} generate_series_fctx;


/***********************************************************************
 **
 **        Routines for 64-bit integers.
 **
 ***********************************************************************/

/*----------------------------------------------------------
 * Formatting and conversion routines.
 *---------------------------------------------------------*/

/*
 * scanint8 --- try to parse a string into an int8.
 *
 * If errorOK is false, ereport a useful error message if the string is bad.
 * If errorOK is true, just return "false" for bad input.
 */
bool
scanint8(const char *str, bool errorOK, int64 *result)
{// #lizard forgives
    const char *ptr = str;
    int64        tmp = 0;
    int            sign = 1;

    /*
     * Do our own scan, rather than relying on sscanf which might be broken
     * for long long.
     */

    /* skip leading spaces */
    while (*ptr && isspace((unsigned char) *ptr))
        ptr++;

    /* handle sign */
    if (*ptr == '-')
    {
        ptr++;

        /*
         * Do an explicit check for INT64_MIN.  Ugly though this is, it's
         * cleaner than trying to get the loop below to handle it portably.
         */
        if (strncmp(ptr, "9223372036854775808", 19) == 0)
        {
            tmp = PG_INT64_MIN;
            ptr += 19;
            goto gotdigits;
        }
        sign = -1;
    }
    else if (*ptr == '+')
        ptr++;

    /* require at least one digit */
    if (!isdigit((unsigned char) *ptr))
    {
        if (errorOK)
            return false;
        else
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                     errmsg("invalid input syntax for %s: \"%s\"",
                            "integer", str)));
    }

    /* process digits */
    while (*ptr && isdigit((unsigned char) *ptr))
    {
        int64        newtmp = tmp * 10 + (*ptr++ - '0');

        if ((newtmp / 10) != tmp)    /* overflow? */
        {
            if (errorOK)
                return false;
            else
                ereport(ERROR,
                        (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                         errmsg("value \"%s\" is out of range for type %s",
                                str, "bigint")));
        }
        tmp = newtmp;
    }

gotdigits:

    /* allow trailing whitespace, but not other trailing chars */
    while (*ptr != '\0' && isspace((unsigned char) *ptr))
        ptr++;

    if (*ptr != '\0')
    {
        if (errorOK)
            return false;
        else
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                     errmsg("invalid input syntax for %s: \"%s\"",
                            "integer", str)));
    }

    *result = (sign < 0) ? -tmp : tmp;

    return true;
}

/* int8in()
 */
Datum
int8in(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);
    int64        result;

    (void) scanint8(str, false, &result);
    PG_RETURN_INT64(result);
}


/* int8out()
 */
Datum
int8out(PG_FUNCTION_ARGS)
{
    int64        val = PG_GETARG_INT64(0);
    char        buf[MAXINT8LEN + 1];
    char       *result;

    pg_lltoa(val, buf);
    result = pstrdup(buf);
    PG_RETURN_CSTRING(result);
}

/*
 *        int8recv            - converts external binary format to int8
 */
Datum
int8recv(PG_FUNCTION_ARGS)
{
    StringInfo    buf = (StringInfo) PG_GETARG_POINTER(0);

    PG_RETURN_INT64(pq_getmsgint64(buf));
}

/*
 *        int8send            - converts int8 to binary format
 */
Datum
int8send(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    StringInfoData buf;

    pq_begintypsend(&buf);
    pq_sendint64(&buf, arg1);
    PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


/*----------------------------------------------------------
 *    Relational operators for int8s, including cross-data-type comparisons.
 *---------------------------------------------------------*/

/* int8relop()
 * Is val1 relop val2?
 */
Datum
int8eq(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 == val2);
}

Datum
int8ne(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 != val2);
}

Datum
int8lt(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 < val2);
}

Datum
int8gt(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 > val2);
}

Datum
int8le(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 <= val2);
}

Datum
int8ge(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 >= val2);
}

/* int84relop()
 * Is 64-bit val1 relop 32-bit val2?
 */
Datum
int84eq(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int32        val2 = PG_GETARG_INT32(1);

    PG_RETURN_BOOL(val1 == val2);
}

Datum
int84ne(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int32        val2 = PG_GETARG_INT32(1);

    PG_RETURN_BOOL(val1 != val2);
}

Datum
int84lt(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int32        val2 = PG_GETARG_INT32(1);

    PG_RETURN_BOOL(val1 < val2);
}

Datum
int84gt(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int32        val2 = PG_GETARG_INT32(1);

    PG_RETURN_BOOL(val1 > val2);
}

Datum
int84le(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int32        val2 = PG_GETARG_INT32(1);

    PG_RETURN_BOOL(val1 <= val2);
}

Datum
int84ge(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int32        val2 = PG_GETARG_INT32(1);

    PG_RETURN_BOOL(val1 >= val2);
}

/* int48relop()
 * Is 32-bit val1 relop 64-bit val2?
 */
Datum
int48eq(PG_FUNCTION_ARGS)
{
    int32        val1 = PG_GETARG_INT32(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 == val2);
}

Datum
int48ne(PG_FUNCTION_ARGS)
{
    int32        val1 = PG_GETARG_INT32(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 != val2);
}

Datum
int48lt(PG_FUNCTION_ARGS)
{
    int32        val1 = PG_GETARG_INT32(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 < val2);
}

Datum
int48gt(PG_FUNCTION_ARGS)
{
    int32        val1 = PG_GETARG_INT32(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 > val2);
}

Datum
int48le(PG_FUNCTION_ARGS)
{
    int32        val1 = PG_GETARG_INT32(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 <= val2);
}

Datum
int48ge(PG_FUNCTION_ARGS)
{
    int32        val1 = PG_GETARG_INT32(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 >= val2);
}

/* int82relop()
 * Is 64-bit val1 relop 16-bit val2?
 */
Datum
int82eq(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int16        val2 = PG_GETARG_INT16(1);

    PG_RETURN_BOOL(val1 == val2);
}

Datum
int82ne(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int16        val2 = PG_GETARG_INT16(1);

    PG_RETURN_BOOL(val1 != val2);
}

Datum
int82lt(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int16        val2 = PG_GETARG_INT16(1);

    PG_RETURN_BOOL(val1 < val2);
}

Datum
int82gt(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int16        val2 = PG_GETARG_INT16(1);

    PG_RETURN_BOOL(val1 > val2);
}

Datum
int82le(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int16        val2 = PG_GETARG_INT16(1);

    PG_RETURN_BOOL(val1 <= val2);
}

Datum
int82ge(PG_FUNCTION_ARGS)
{
    int64        val1 = PG_GETARG_INT64(0);
    int16        val2 = PG_GETARG_INT16(1);

    PG_RETURN_BOOL(val1 >= val2);
}

/* int28relop()
 * Is 16-bit val1 relop 64-bit val2?
 */
Datum
int28eq(PG_FUNCTION_ARGS)
{
    int16        val1 = PG_GETARG_INT16(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 == val2);
}

Datum
int28ne(PG_FUNCTION_ARGS)
{
    int16        val1 = PG_GETARG_INT16(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 != val2);
}

Datum
int28lt(PG_FUNCTION_ARGS)
{
    int16        val1 = PG_GETARG_INT16(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 < val2);
}

Datum
int28gt(PG_FUNCTION_ARGS)
{
    int16        val1 = PG_GETARG_INT16(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 > val2);
}

Datum
int28le(PG_FUNCTION_ARGS)
{
    int16        val1 = PG_GETARG_INT16(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 <= val2);
}

Datum
int28ge(PG_FUNCTION_ARGS)
{
    int16        val1 = PG_GETARG_INT16(0);
    int64        val2 = PG_GETARG_INT64(1);

    PG_RETURN_BOOL(val1 >= val2);
}


/*----------------------------------------------------------
 *    Arithmetic operators on 64-bit integers.
 *---------------------------------------------------------*/

Datum
int8um(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);
    int64        result;

    result = -arg;
    /* overflow check (needed for INT64_MIN) */
    if (arg != 0 && SAMESIGN(result, arg))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int8up(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);

    PG_RETURN_INT64(arg);
}

Datum
int8pl(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 + arg2;

    /*
     * Overflow check.  If the inputs are of different signs then their sum
     * cannot overflow.  If the inputs are of the same sign, their sum had
     * better be that sign too.
     */
    if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int8mi(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 - arg2;

    /*
     * Overflow check.  If the inputs are of the same sign then their
     * difference cannot overflow.  If they are of different signs then the
     * result should be of the same sign as the first input.
     */
    if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int8mul(PG_FUNCTION_ARGS)
{// #lizard forgives
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 * arg2;

    /*
     * Overflow check.  We basically check to see if result / arg2 gives arg1
     * again.  There are two cases where this fails: arg2 = 0 (which cannot
     * overflow) and arg1 = INT64_MIN, arg2 = -1 (where the division itself
     * will overflow and thus incorrectly match).
     *
     * Since the division is likely much more expensive than the actual
     * multiplication, we'd like to skip it where possible.  The best bang for
     * the buck seems to be to check whether both inputs are in the int32
     * range; if so, no overflow is possible.
     */
    if (arg1 != (int64) ((int32) arg1) || arg2 != (int64) ((int32) arg2))
    {
        if (arg2 != 0 &&
            ((arg2 == -1 && arg1 < 0 && result < 0) ||
             result / arg2 != arg1))
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));
    }
    PG_RETURN_INT64(result);
}

Datum
int8div(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    if (arg2 == 0)
    {
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
        /* ensure compiler realizes we mustn't reach the division (gcc bug) */
        PG_RETURN_NULL();
    }

    /*
     * INT64_MIN / -1 is problematic, since the result can't be represented on
     * a two's-complement machine.  Some machines produce INT64_MIN, some
     * produce zero, some throw an exception.  We can dodge the problem by
     * recognizing that division by -1 is the same as negation.
     */
    if (arg2 == -1)
    {
        result = -arg1;
        /* overflow check (needed for INT64_MIN) */
        if (arg1 != 0 && SAMESIGN(result, arg1))
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));
        PG_RETURN_INT64(result);
    }

    /* No overflow is possible */

    result = arg1 / arg2;

    PG_RETURN_INT64(result);
}

/* int8abs()
 * Absolute value
 */
Datum
int8abs(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        result;

    result = (arg1 < 0) ? -arg1 : arg1;
    /* overflow check (needed for INT64_MIN) */
    if (result < 0)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

/* int8mod()
 * Modulo operation.
 */
Datum
int8mod(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);

    if (arg2 == 0)
    {
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
        /* ensure compiler realizes we mustn't reach the division (gcc bug) */
        PG_RETURN_NULL();
    }

    /*
     * Some machines throw a floating-point exception for INT64_MIN % -1,
     * which is a bit silly since the correct answer is perfectly
     * well-defined, namely zero.
     */
    if (arg2 == -1)
        PG_RETURN_INT64(0);

    /* No overflow is possible */

    PG_RETURN_INT64(arg1 % arg2);
}


Datum
int8inc(PG_FUNCTION_ARGS)
{
    /*
     * When int8 is pass-by-reference, we provide this special case to avoid
     * palloc overhead for COUNT(): when called as an aggregate, we know that
     * the argument is modifiable local storage, so just update it in-place.
     * (If int8 is pass-by-value, then of course this is useless as well as
     * incorrect, so just ifdef it out.)
     */
#ifndef USE_FLOAT8_BYVAL        /* controls int8 too */
    if (AggCheckCallContext(fcinfo, NULL))
    {
        int64       *arg = (int64 *) PG_GETARG_POINTER(0);
        int64        result;

        result = *arg + 1;
        /* Overflow check */
        if (result < 0 && *arg > 0)
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));

        *arg = result;
        PG_RETURN_POINTER(arg);
    }
    else
#endif
    {
        /* Not called as an aggregate, so just do it the dumb way */
        int64        arg = PG_GETARG_INT64(0);
        int64        result;

        result = arg + 1;
        /* Overflow check */
        if (result < 0 && arg > 0)
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));

        PG_RETURN_INT64(result);
    }
}

Datum
int8dec(PG_FUNCTION_ARGS)
{
    /*
     * When int8 is pass-by-reference, we provide this special case to avoid
     * palloc overhead for COUNT(): when called as an aggregate, we know that
     * the argument is modifiable local storage, so just update it in-place.
     * (If int8 is pass-by-value, then of course this is useless as well as
     * incorrect, so just ifdef it out.)
     */
#ifndef USE_FLOAT8_BYVAL        /* controls int8 too */
    if (AggCheckCallContext(fcinfo, NULL))
    {
        int64       *arg = (int64 *) PG_GETARG_POINTER(0);
        int64        result;

        result = *arg - 1;
        /* Overflow check */
        if (result > 0 && *arg < 0)
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));

        *arg = result;
        PG_RETURN_POINTER(arg);
    }
    else
#endif
    {
        /* Not called as an aggregate, so just do it the dumb way */
        int64        arg = PG_GETARG_INT64(0);
        int64        result;

        result = arg - 1;
        /* Overflow check */
        if (result > 0 && arg < 0)
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));

        PG_RETURN_INT64(result);
    }
}


/*
 * These functions are exactly like int8inc/int8dec but are used for
 * aggregates that count only non-null values.  Since the functions are
 * declared strict, the null checks happen before we ever get here, and all we
 * need do is increment the state value.  We could actually make these pg_proc
 * entries point right at int8inc/int8dec, but then the opr_sanity regression
 * test would complain about mismatched entries for a built-in function.
 */

Datum
int8inc_any(PG_FUNCTION_ARGS)
{
    return int8inc(fcinfo);
}

Datum
int8inc_float8_float8(PG_FUNCTION_ARGS)
{
    return int8inc(fcinfo);
}

Datum
int8dec_any(PG_FUNCTION_ARGS)
{
    return int8dec(fcinfo);
}


Datum
int8larger(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = ((arg1 > arg2) ? arg1 : arg2);

    PG_RETURN_INT64(result);
}

Datum
int8smaller(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = ((arg1 < arg2) ? arg1 : arg2);

    PG_RETURN_INT64(result);
}

Datum
int84pl(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int32        arg2 = PG_GETARG_INT32(1);
    int64        result;

    result = arg1 + arg2;

    /*
     * Overflow check.  If the inputs are of different signs then their sum
     * cannot overflow.  If the inputs are of the same sign, their sum had
     * better be that sign too.
     */
    if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int84mi(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int32        arg2 = PG_GETARG_INT32(1);
    int64        result;

    result = arg1 - arg2;

    /*
     * Overflow check.  If the inputs are of the same sign then their
     * difference cannot overflow.  If they are of different signs then the
     * result should be of the same sign as the first input.
     */
    if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int84mul(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int32        arg2 = PG_GETARG_INT32(1);
    int64        result;

    result = arg1 * arg2;

    /*
     * Overflow check.  We basically check to see if result / arg1 gives arg2
     * again.  There is one case where this fails: arg1 = 0 (which cannot
     * overflow).
     *
     * Since the division is likely much more expensive than the actual
     * multiplication, we'd like to skip it where possible.  The best bang for
     * the buck seems to be to check whether both inputs are in the int32
     * range; if so, no overflow is possible.
     */
    if (arg1 != (int64) ((int32) arg1) &&
        result / arg1 != arg2)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int84div(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int32        arg2 = PG_GETARG_INT32(1);
    int64        result;

    if (arg2 == 0)
    {
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
        /* ensure compiler realizes we mustn't reach the division (gcc bug) */
        PG_RETURN_NULL();
    }

    /*
     * INT64_MIN / -1 is problematic, since the result can't be represented on
     * a two's-complement machine.  Some machines produce INT64_MIN, some
     * produce zero, some throw an exception.  We can dodge the problem by
     * recognizing that division by -1 is the same as negation.
     */
    if (arg2 == -1)
    {
        result = -arg1;
        /* overflow check (needed for INT64_MIN) */
        if (arg1 != 0 && SAMESIGN(result, arg1))
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));
        PG_RETURN_INT64(result);
    }

    /* No overflow is possible */

    result = arg1 / arg2;

    PG_RETURN_INT64(result);
}

Datum
int48pl(PG_FUNCTION_ARGS)
{
    int32        arg1 = PG_GETARG_INT32(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 + arg2;

    /*
     * Overflow check.  If the inputs are of different signs then their sum
     * cannot overflow.  If the inputs are of the same sign, their sum had
     * better be that sign too.
     */
    if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int48mi(PG_FUNCTION_ARGS)
{
    int32        arg1 = PG_GETARG_INT32(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 - arg2;

    /*
     * Overflow check.  If the inputs are of the same sign then their
     * difference cannot overflow.  If they are of different signs then the
     * result should be of the same sign as the first input.
     */
    if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int48mul(PG_FUNCTION_ARGS)
{
    int32        arg1 = PG_GETARG_INT32(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 * arg2;

    /*
     * Overflow check.  We basically check to see if result / arg2 gives arg1
     * again.  There is one case where this fails: arg2 = 0 (which cannot
     * overflow).
     *
     * Since the division is likely much more expensive than the actual
     * multiplication, we'd like to skip it where possible.  The best bang for
     * the buck seems to be to check whether both inputs are in the int32
     * range; if so, no overflow is possible.
     */
    if (arg2 != (int64) ((int32) arg2) &&
        result / arg2 != arg1)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int48div(PG_FUNCTION_ARGS)
{
    int32        arg1 = PG_GETARG_INT32(0);
    int64        arg2 = PG_GETARG_INT64(1);

    if (arg2 == 0)
    {
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
        /* ensure compiler realizes we mustn't reach the division (gcc bug) */
        PG_RETURN_NULL();
    }

    /* No overflow is possible */
    PG_RETURN_INT64((int64) arg1 / arg2);
}

Datum
int82pl(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int16        arg2 = PG_GETARG_INT16(1);
    int64        result;

    result = arg1 + arg2;

    /*
     * Overflow check.  If the inputs are of different signs then their sum
     * cannot overflow.  If the inputs are of the same sign, their sum had
     * better be that sign too.
     */
    if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int82mi(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int16        arg2 = PG_GETARG_INT16(1);
    int64        result;

    result = arg1 - arg2;

    /*
     * Overflow check.  If the inputs are of the same sign then their
     * difference cannot overflow.  If they are of different signs then the
     * result should be of the same sign as the first input.
     */
    if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int82mul(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int16        arg2 = PG_GETARG_INT16(1);
    int64        result;

    result = arg1 * arg2;

    /*
     * Overflow check.  We basically check to see if result / arg1 gives arg2
     * again.  There is one case where this fails: arg1 = 0 (which cannot
     * overflow).
     *
     * Since the division is likely much more expensive than the actual
     * multiplication, we'd like to skip it where possible.  The best bang for
     * the buck seems to be to check whether both inputs are in the int32
     * range; if so, no overflow is possible.
     */
    if (arg1 != (int64) ((int32) arg1) &&
        result / arg1 != arg2)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int82div(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int16        arg2 = PG_GETARG_INT16(1);
    int64        result;

    if (arg2 == 0)
    {
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
        /* ensure compiler realizes we mustn't reach the division (gcc bug) */
        PG_RETURN_NULL();
    }

    /*
     * INT64_MIN / -1 is problematic, since the result can't be represented on
     * a two's-complement machine.  Some machines produce INT64_MIN, some
     * produce zero, some throw an exception.  We can dodge the problem by
     * recognizing that division by -1 is the same as negation.
     */
    if (arg2 == -1)
    {
        result = -arg1;
        /* overflow check (needed for INT64_MIN) */
        if (arg1 != 0 && SAMESIGN(result, arg1))
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("bigint out of range")));
        PG_RETURN_INT64(result);
    }

    /* No overflow is possible */

    result = arg1 / arg2;

    PG_RETURN_INT64(result);
}

Datum
int28pl(PG_FUNCTION_ARGS)
{
    int16        arg1 = PG_GETARG_INT16(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 + arg2;

    /*
     * Overflow check.  If the inputs are of different signs then their sum
     * cannot overflow.  If the inputs are of the same sign, their sum had
     * better be that sign too.
     */
    if (SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int28mi(PG_FUNCTION_ARGS)
{
    int16        arg1 = PG_GETARG_INT16(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 - arg2;

    /*
     * Overflow check.  If the inputs are of the same sign then their
     * difference cannot overflow.  If they are of different signs then the
     * result should be of the same sign as the first input.
     */
    if (!SAMESIGN(arg1, arg2) && !SAMESIGN(result, arg1))
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int28mul(PG_FUNCTION_ARGS)
{
    int16        arg1 = PG_GETARG_INT16(0);
    int64        arg2 = PG_GETARG_INT64(1);
    int64        result;

    result = arg1 * arg2;

    /*
     * Overflow check.  We basically check to see if result / arg2 gives arg1
     * again.  There is one case where this fails: arg2 = 0 (which cannot
     * overflow).
     *
     * Since the division is likely much more expensive than the actual
     * multiplication, we'd like to skip it where possible.  The best bang for
     * the buck seems to be to check whether both inputs are in the int32
     * range; if so, no overflow is possible.
     */
    if (arg2 != (int64) ((int32) arg2) &&
        result / arg2 != arg1)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));
    PG_RETURN_INT64(result);
}

Datum
int28div(PG_FUNCTION_ARGS)
{
    int16        arg1 = PG_GETARG_INT16(0);
    int64        arg2 = PG_GETARG_INT64(1);

    if (arg2 == 0)
    {
        ereport(ERROR,
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
        /* ensure compiler realizes we mustn't reach the division (gcc bug) */
        PG_RETURN_NULL();
    }

    /* No overflow is possible */
    PG_RETURN_INT64((int64) arg1 / arg2);
}

/* Binary arithmetics
 *
 *        int8and        - returns arg1 & arg2
 *        int8or        - returns arg1 | arg2
 *        int8xor        - returns arg1 # arg2
 *        int8not        - returns ~arg1
 *        int8shl        - returns arg1 << arg2
 *        int8shr        - returns arg1 >> arg2
 */

Datum
int8and(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);

    PG_RETURN_INT64(arg1 & arg2);
}

Datum
int8or(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);

    PG_RETURN_INT64(arg1 | arg2);
}

Datum
int8xor(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int64        arg2 = PG_GETARG_INT64(1);

    PG_RETURN_INT64(arg1 ^ arg2);
}

Datum
int8not(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);

    PG_RETURN_INT64(~arg1);
}

Datum
int8shl(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int32        arg2 = PG_GETARG_INT32(1);

    PG_RETURN_INT64(arg1 << arg2);
}

Datum
int8shr(PG_FUNCTION_ARGS)
{
    int64        arg1 = PG_GETARG_INT64(0);
    int32        arg2 = PG_GETARG_INT32(1);

    PG_RETURN_INT64(arg1 >> arg2);
}

/*----------------------------------------------------------
 *    Conversion operators.
 *---------------------------------------------------------*/

Datum
int48(PG_FUNCTION_ARGS)
{
    int32        arg = PG_GETARG_INT32(0);

    PG_RETURN_INT64((int64) arg);
}

Datum
int84(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);
    int32        result;

    result = (int32) arg;

    /* Test for overflow by reverse-conversion. */
    if ((int64) result != arg)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("integer out of range")));

    PG_RETURN_INT32(result);
}

Datum
int28(PG_FUNCTION_ARGS)
{
    int16        arg = PG_GETARG_INT16(0);

    PG_RETURN_INT64((int64) arg);
}

Datum
int82(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);
    int16        result;

    result = (int16) arg;

    /* Test for overflow by reverse-conversion. */
    if ((int64) result != arg)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("smallint out of range")));

    PG_RETURN_INT16(result);
}

Datum
i8tod(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);
    float8        result;

    result = arg;

    PG_RETURN_FLOAT8(result);
}

/* dtoi8()
 * Convert float8 to 8-byte integer.
 */
Datum
dtoi8(PG_FUNCTION_ARGS)
{
    float8        arg = PG_GETARG_FLOAT8(0);
    int64        result;

    /* Round arg to nearest integer (but it's still in float form) */
    arg = rint(arg);

    /*
     * Does it fit in an int64?  Avoid assuming that we have handy constants
     * defined for the range boundaries, instead test for overflow by
     * reverse-conversion.
     */
    result = (int64) arg;

    if ((float8) result != arg)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));

    PG_RETURN_INT64(result);
}

Datum
i8tof(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);
    float4        result;

    result = arg;

    PG_RETURN_FLOAT4(result);
}

/* ftoi8()
 * Convert float4 to 8-byte integer.
 */
Datum
ftoi8(PG_FUNCTION_ARGS)
{
    float4        arg = PG_GETARG_FLOAT4(0);
    int64        result;
    float8        darg;

    /* Round arg to nearest integer (but it's still in float form) */
    darg = rint(arg);

    /*
     * Does it fit in an int64?  Avoid assuming that we have handy constants
     * defined for the range boundaries, instead test for overflow by
     * reverse-conversion.
     */
    result = (int64) darg;

    if ((float8) result != darg)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("bigint out of range")));

    PG_RETURN_INT64(result);
}

Datum
i8tooid(PG_FUNCTION_ARGS)
{
    int64        arg = PG_GETARG_INT64(0);
    Oid            result;

    result = (Oid) arg;

    /* Test for overflow by reverse-conversion. */
    if ((int64) result != arg)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("OID out of range")));

    PG_RETURN_OID(result);
}

Datum
oidtoi8(PG_FUNCTION_ARGS)
{
    Oid            arg = PG_GETARG_OID(0);

    PG_RETURN_INT64((int64) arg);
}

/*
 * non-persistent numeric series generator
 */
Datum
generate_series_int8(PG_FUNCTION_ARGS)
{
    return generate_series_step_int8(fcinfo);
}

Datum
generate_series_step_int8(PG_FUNCTION_ARGS)
{// #lizard forgives
    FuncCallContext *funcctx;
    generate_series_fctx *fctx;
    int64        result;
    MemoryContext oldcontext;

    /* stuff done only on the first call of the function */
    if (SRF_IS_FIRSTCALL())
    {
        int64        start = PG_GETARG_INT64(0);
        int64        finish = PG_GETARG_INT64(1);
        int64        step = 1;

        /* see if we were given an explicit step size */
        if (PG_NARGS() == 3)
            step = PG_GETARG_INT64(2);
        if (step == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                     errmsg("step size cannot equal zero")));

        /* create a function context for cross-call persistence */
        funcctx = SRF_FIRSTCALL_INIT();

        /*
         * switch to memory context appropriate for multiple function calls
         */
        oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

        /* allocate memory for user context */
        fctx = (generate_series_fctx *) palloc(sizeof(generate_series_fctx));

        /*
         * Use fctx to keep state from call to call. Seed current with the
         * original start value
         */
        fctx->current = start;
        fctx->finish = finish;
        fctx->step = step;

        funcctx->user_fctx = fctx;
        MemoryContextSwitchTo(oldcontext);
    }

    /* stuff done on every call of the function */
    funcctx = SRF_PERCALL_SETUP();

    /*
     * get the saved state and use current as the result for this iteration
     */
    fctx = funcctx->user_fctx;
    result = fctx->current;

    if ((fctx->step > 0 && fctx->current <= fctx->finish) ||
        (fctx->step < 0 && fctx->current >= fctx->finish))
    {
        /* increment current in preparation for next iteration */
        fctx->current += fctx->step;

        /* if next-value computation overflows, this is the final result */
        if (SAMESIGN(result, fctx->step) && !SAMESIGN(result, fctx->current))
            fctx->step = 0;

        /* do when there is more left to send */
        SRF_RETURN_NEXT(funcctx, Int64GetDatum(result));
    }
    else
        /* do when there is no more left */
        SRF_RETURN_DONE(funcctx);
}
